Polyolefins such as polyethylene, polypropylene and copolymers of ethylene and propylene are commercially important materials used as thermoplastics and elastomers. Polyolefins are widely used in a variety of applications including but not limited to packaging, molding, automotive rubber parts, and adhesives.
In contrast to the volumes of work describing early metal group 4-6 olefin polymerization catalysts, there have been relatively few reports of group 10 catalysts for the polymerization of olefins. WO Patent Application 96/23010 describes the polymerization of olefins using cationic nickel, palladium, iron, and cobalt complexes containing diimine and bisoxazoline ligands. WO Patent Application 96/23010 also describes a series of novel polyolefins based on ethylene homopolymer and copolymers, as well as, homo- and copolymers of alpha-olefins including propylene, 1-hexene, and methylacrylate, among others.
European Patent Application Serial No. 381,495 describes the polymerization of olefins using palladium and nickel catalysts which contain selected bidentate phosphorous containing ligands.
Cationic .alpha.-diimine-based nickel and palladium complexes have been described by Brookhart and coworkers as highly efficient olefin and .alpha.-olefin polymerization catalysts (Johnson, L. K.; Killian, C. M.; Brookhart, M. J. Am. Chem. Soc. 1995, 117, 6414). These catalysts polymerize ethylene to high molecular weight branched polyethylene. In addition to ethylene, these complexes act as catalysts for the polymerization and copolymerization of .alpha.-olefins (e.g. propylene, 1-hexene, methyl acrylate).
Schmidt and coworkers have also described a cobalt(III) cyclopentadienyl system of the general structure [C.sub.5 Me.sub.5 (L)CoCH.sub.2 CH.sub.2 --.mu.--H].sup.+ (Schmidt, G. F.; Brookhart, M. J. Am. Chem. Soc. 1985, 107,1443). These catalysts effect the "living" polymerization of ethylene. The living nature of these catalysts has been exploited for the synthesis of end-functionalized polyethylene homopolymers (Brookhart, M.; DeSimone, J. M.; Grant, B. E.; Tanner, M. J. Macromolecules 1995, 28, 5378). U. Klabunde, U.S. Pat. Nos. 4,906,754; 4,716,205; 5,030,606; 5,175,326 describe the conversion of ethylene to polyethylene using anionic phosphorous, oxygen donors ligated to Ni(II). The polymerization reactions were conducted between 25 and 100.degree. C. with modest yields, producing linear polyethylene having a weight-average molecular weight ranging between 8K and 350 K.
Peukert and Keim reported the oligomerization of ethylene using a phosphine carboxylate chelate ligand, which showed modest activity (0.14 to 1.83 TO/s). The oligomerizations were carried out at 60 to 95.degree. C. and 10 to 80 bar ethylene in toluene, to produce linear .alpha.-olefins (Peuckert, M.; Keim, W. Organomet. 1983, 2(5), 594).
In addition, Murray has described the oligomerization of ethylene using phosphine sulphonate chelate ligands. These complexes show catalyst activities about 15 times greater than the activities reported for the phosphine carboxylate analogs described above (R. E. Murray U.S. Pat. Nos. 4,689,437 and 4,716,138,1987).
The polymerization of ethylene and the oligomerization of .alpha.-olefins with [aminobis(imino)phosphorane]nickel catalysts has also been described (Keim, W.; Appel, R.; Storeck, A.; Kruger, C.; Goddard, R. Angew. Chem. Int. Ed. Eng. 1981, 20,116. Mohring, V. M.; Fink, G. Angew. Chem. Int. Ed. Eng. 1985, 24,1001). Other group 10 catalysts known in the art include a nickel allyl phosphine complex described by Wilke (Wilke, G. Angew. Chem. lnt. Ed. Engl. 1988, 27,185), and a series of Bis(ylide) nickel complexes which are reported by K. Alexander Ostoja Starzewski to polymerize ethylene to high molecular weight linear polyethylene (Starzewski, K. A. O.; Witte, J. Angew. Chem. Int. Ed. Engl. 1987, 26, 63).
WO Patent Application 97/02298 discloses the polymerization of olefins using a variety of neutral N, O, P, or S donor ligands, in combination with a nickel(0) compound and an acid.
Fink et al., U.S. Pat. No. 4,724,273, describes the polymerization of .alpha.-olefins using aminobis(imino)phosphorane nickel catalysts and the compositions of the resulting poly(.alpha.-olefins).
Additional recent developments are described by Sugimura et al., in JP96-84344, JP96-84343 and WO 9738024, and by Yorisue et al., in JP96-70332.